Primate of the Week: Proboscis monkey

Nasalis larvatus

ARKive image GES006356 - Proboscis monkey

Photo from ARKive of the Proboscis monkey (Nasalis larvatus) – http://www.arkive.org/proboscis-monkey/nasalis-larvatus/image-G6356.html

Taxonomy
Suborder: Haplorrhini
Infraorder: Simiiformes
Superfamily: Cercopithecoidea
Family: Cercopithecidae
Subfamily: Colobinae

ARKive image GES019668 - Proboscis monkey

Photo from ARKive of the Proboscis monkey (Nasalis larvatus) – http://www.arkive.org/proboscis-monkey/nasalis-larvatus/image-G19668.html

Proboscis monkeys are old world monkeys and one of the largest colobines (subfamily of old world monkeys) They are sexual dimorphic. Males on average are 75.5 cm in length while females are on average 62 cm in length (Napier and Napier, 1985; Bennet and Sebastian, 1988; Ankel-Simons, 2007). Males weigh approximately 20kg while females weigh nearly half that (Napier and Napier, 1985; Bennett and Gombek, 1993). Both females and males have large noses, however the males nose is far larger (Payne et al., 1985; Ankel-Simon, 2007). A male’s nose can reach over 10 cm (Ellis, 1986).

ARKive image GES019667 - Proboscis monkey

Photo from ARKive of the Proboscis monkey (Nasalis larvatus) – http://www.arkive.org/proboscis-monkey/nasalis-larvatus/image-G19667.html

Proboscis monkeys range from bright orange to brick red dorsally and light gray to light orange ventrally (Kern, 1964; Payne et al., 1985; Groves, 2001; Ankel-Simons, 2007). The males are characterized by a red penis (Kern, 1964; Ankel-Simon, 2007). Adult males also have dark brown mane on their back (Bennett and Gombek, 1993). Like other old world monkeys, Proboscis monkeys have an ischial callosites (Bennett and Gombek, 1993; Groves, 2001; Ankel-Simons, 2007).

ARKive image GES014246 - Proboscis monkey

Photo from ARKive of the Proboscis monkey (Nasalis larvatus) – http://www.arkive.org/proboscis-monkey/nasalis-larvatus/image-G14246.html

Proboscis monkeys are found in Borneo in lowland forests (Bennett and Sebastian, 1988; Salter et al., 1985; Sebastian, 2000; Brandon-Jones et al., 2004).

ARKive image GES005664 - Proboscis monkey

Photo from ARKive of the Proboscis monkey (Nasalis larvatus) – http://www.arkive.org/proboscis-monkey/nasalis-larvatus/image-G5664.html

Proboscis monkeys are both frugivores and folivores depending on the season. They have been described as feeding on over 90 species of plants (Salter et al., 1985; Boonratana, 1993; Yeager, 1989).

ARKive image GES019663 - Proboscis monkey

Photo from ARKive of the Proboscis monkey (Nasalis larvatus) – http://www.arkive.org/proboscis-monkey/nasalis-larvatus/image-G19663.html

Proboscis monkeys groups tend to be one male unit with a single male, several females and their offspring (Bennett and Sebastian, 1988; Rajanthan and Bennett, 1990; Yeager, 1990; 1992; Bennett and Gombek ,1993; Boonratana, 1993; Yeager, 1995; Boonratana, 2002; Murai, 2004). However, solitary and all male groups have been observed (Bennett and Sebastian, 1988; Yeager, 1990; 1992; Boonratana,1993; Yeager, 1995; Boonratana, 1999; 2002; Murai, 2004).The one male units also appear to be part of a larger group that has fission fussion and aggregates at night (Macdonald, 1982; Bennett and Sebastian, 1988; Rajanthan and Bennett, 1990; Bennett and Gombek, 1993; Boonratana, 1993; Yeager, 1995; Boonratana, 2002). Group size varies from 9 to 19 individuals in the one male unit groups but these groups often aggregate to up to 60 individuals (Kawabe and Mano, 1972; Macdonald, 1982; Salter and Aken, 1983; Ruhiyat, 1986; Bennett and Sebastian, 1988; Rajanthan and Bennett, 1990; Yeager, 1992; Bennett and Gombek, 1993; Boonratana, 1999; Murai et al,. 2007). Resident males of the one male units have a tenure of 6 to 8 years (Murai, 2004, Murai et al., 2007).

ARKive image GES006867 - Proboscis monkey

Photo from ARKive of the Proboscis monkey (Nasalis larvatus) – http://www.arkive.org/proboscis-monkey/nasalis-larvatus/image-G6867.html

Males will leave their natal group before adulthood and will often join all male groups (Rajanathan and Bennett, 1990; Yeager, 1990; Bennett and Gombek, 1993; Boonratana, 1999). Adult females and sub adult females will also transfer groups (Bennett and Sebastian, 1988; Boonratana, 1993; 1999; Murai et al., 2007).

ARKive image GES005665 - Proboscis monkey

Photo from ARKive of the Proboscis monkey (Nasalis larvatus) – http://www.arkive.org/proboscis-monkey/nasalis-larvatus/image-G5665.html

Females are sexually mature at five years of age (Murai, 2004). Femakes also show sexual swellings in which their genital pink and redden (Gorzitze, 1996; Murai, 2004; 2006).

ARKive image GES031458 - Proboscis monkey

Photo from ARKive of the Proboscis monkey (Nasalis larvatus) – http://www.arkive.org/proboscis-monkey/nasalis-larvatus/image-G31458.html

References/ read more

Ankel-Simons F. 2007. Primate Anatomy: an introduction, 3rd Edition. San Diego: Elsevier Acad Pr. 724 p.
Bennett EL, Caldecott JO, Kavanagh M, Sebastian AC. 1987. Current status of primates in Sarawak. Primate Conserv 8:184-6.
Bennett EL. 1988. Proboscis monkeys and their swamp forests in Sarawak. Oryx 22(2):69-74.
Bennett EL, Gombek F. 1993. Proboscis monkeys of Borneo. Sabah (MY):Koktas Sabah Berhad Ranau. 75p.
Bennett EL, Sebastian AC. 1988. Social organization and ecology of Proboscis monkeys (Nasalis larvatus) in mixed coastal forest in Sarawak. Int J Primatol 9(:233-55.
Boonratana R, Sharma DS. 1992. Conservation of proboscis monkeys in the lower Kinabatangan, Sabah. In: Thierry B, Anderson JR, Roeder JJ, Herrenschmidt N, editors. Current primatology, volume I: ecology and evolution. Strasbourg (FR):Universite Louis Pasteur. p93-100.
Boonratana R. 1999. Dispersal in proboscis monkeys (Nasalis larvatus) in the lower Kinabatangan, Northern Borneo. Tropic Biodiv 6(3):179-87.
Boonratana R. 1993. The ecology and behaviour of the proboscis monkey (Nasalis larvatus) in the lower Kinabatangan, Sabah. PhD dissertation, Mahidol University. 275p.
Boonratana R. 2003. Feeding ecology of proboscis monkeys (Nasalis larvatus) in the lower Kinabatangan, Sabah, Malaysia. Sabah Parks Nat J 6:1-26.
Boonratana R. 2000. Ranging behavior of proboscis monkeys (Nasalis larvatus) in the lower Kinabatangan, northern Borneo. Int J Primatol 21(3):497-518.
Boonratana R. 2002. Social ooranisation of proboscis monkeys (Nasalis larvatus) in the lower Kinabatangan, Sabah, Malaysia. Malay Nat J 56(1):57-75.
Brandon-Jones D, Eudey AA, Geissmann T, Groves CP, Melnick DJ, Morales JC, Shekelle M, Stewart C-B. 2004. Asian primate classification. Int J Primatol 25(1):97-164.
Ellis D. 1986. Proboscis monkey and aquatic ape. Sarawak Mus J 36(57):251-62.
Galdikas BMF. 1985. Crocodile predation on a proboscis monkey in Borneo. Primates 26(4):495-6.
Gorzitze AB. 1996. Birth-related behavior in wild proboscis monkeys (Nasalis larvatus). Primates 37(1):75-8.
Groves C. 2001. Primate taxonomy. Washington DC: Smithsonian Inst Pr. 350 p.
Kawabe M, Mano T. 1972. Ecology and behavior of the wild proboscis monkey, Nasalis larvatus (Wurmb) in Sabah, Malaysia. Primates 13(2):213-28.
Kern JA. 1964. Observations on the habits of the proboscis monkey, Nasalis larvatus (Wurmb), made in the Brunei Bay area, Borneo. Zoologica 49:183-92.
Macdonald DW. 1982. Notes on the size and composition of groups of proboscis monkey, Nasalis larvatus. Folia Primatol 37:95-8.
Messeri P, Trombi M. 2000. Vocal repertoire of proboscis monkey (Nasalis larvatus, L.) in Sarawak. Folia Primatol 71(4):268-87.
Murai T, Mohamed M, Bernard H, Mahedi AP, Saburi R, Higashi S. 2007. Female transfer between one-male groups of proboscis monkey (Nasalis larvatus). Primates 48(2):117-21.
Murai T. 2006. Mating behaviors of the proboscis monkey (Nasalis larvatus). Am J Primatol 68(8):832-7.
Murai T. 2004. Social behaviors of all-male proboscis monkeys when joined by females. Ecol Res 19(4):451-4.
Rajanathan R, Bennett EL. 1990. Notes on the social behaviour of wild proboscis monkeys (Nasalis larvatus). Malay Nat J 44(1):35-44.
Ruhiyat Y. 1986. Preliminary study of proboscis monkey (Nasalis larvatus) in Gunung Palung Nature Reserve, West Kalimantan. Kyoto U Overseas Res Rep Studies Asian Non-Hum Prim 5:59-69.
Salter RE, MacKenzie NA, Nightingale N, Aken KM, Chai PK P. 1985. Habitat use, ranging behaviour, and food habits of the proboscis monkey, Nasalis larvatus (van Wurmb), in Sarawak. Primates 26(4):436-51.
Salter RE, Aken KM. 1983. The proboscis monkey in Bako National Park, Sarawak. Tigerpaper 10(3):6-8.
Sebastian AC. 2000. Proboscis monkeys in Danau Sentarum National Park. Borneo Res Bull 31:359-71.
Soendjoto MA. 2004. A new record on habitat of the proboscis monkey (Nasalis larvatus) and its problems in south Kalimantan, Indonesia. Tigerpaper 31(2):17-8.
Yeager CP. 1992a. Changes in proboscis monkey (Nasalis larvatus) group size and density at Tanjung Putting National Park, Kalimantan Tengah, Indonesia. Trop Biodiv 1(1):49-55.
Yeager CP. 1995. Does intraspecific variation in social systems explain reported differences in the social structure of the proboscis monkey (Nasalis larvatus)? Primates 36(4):575-82.
Yeager CP. 1989a. Feeding ecology of the proboscis monkey (Nasalis larvatus). Int J Primatol 10(6):497-530.
Yeager CP. 1991. Possible antipredator behavior associated with river crossings by proboscis monkeys (Nasalis larvatus). Am J Primatol 24(1):61-6.
Yeager CP. 1989b. Proboscis monkey (Nasalis larvatus) social organization and ecology. PhD dissertation, University of California-Davis. 140p.
Yeager CP. 1990a. Notes on the sexual behavior of the proboscis monkey (Nasalis larvatus). Am J Primatol 21(3):233-7.
Yeager CP. 1990b. Proboscis monkey (Nasalis larvatus) social organization: group structure. Am J Primatol 20(2):95-106.
Yeager CP. 1992b. Proboscis monkey (Nasalis larvatus) social organization: nature and possible functions of intergroup patterns of association. Am J Primatol 26(2):133-7.

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